The present invention is directed to a process for the recovery of non-aqueous type fills from gelatin capsules including hard and soft gelatin capsules in which the capsules are heated with a suitable solvent (e.g. water) until the capsules dissolve and separate into a lower solvent phase containing solvent, gelatin, plasticizer and, if applicable, solvent soluble dyes and other solvent soluble components and an upper non-solvent phase containing the non-solvent fill. The two phases are separated and the non-solvent phase may be further processed to remove any residual solvent and the solvent phase may be further processed to recover the gelatin, plasticizer and, if applicable, dyes and other solvent soluble components.
Methods for recovering non-solvent type fills (e.g. non-aqueous fills as referred to hereinafter) from hard and soft gelatin materials, typically in the form of capsules, are known in the art. Such methods are inefficient and are generally only applicable to recovery of a few fills such as vitamin E. A typical prior art method includes chopping capsules into fine pieces and allowing the non-aqueous fill to either drip off the chopped capsules by gravity or, alternatively, vacuum is applied to the chopped capsules and the recovered non-aqueous fill collected. As used herein, the term capsules refers to any capsules obtained from a capsule producing process which are not saleable for reasons including, but not limited to, cloudiness, malformation, incorrect fill quantity, or expired commercial lots returned to the manufacturer.
Such prior art methods achieve only from about 30% to 70% recovery of the non-aqueous fill, principally due to the viscous nature of the recoverable material.
It would be a significant benefit in the art of removing non-solvent fills (e.g. non-aqueous fills) from gelatin capsules to improve the recovery of the non-aqueous fill, and especially for a process having recovery rates consistently exceeding 90%.
The present invention is generally directed to a process and apparatus for recovering non-solvent type fills (e.g. non-aqueous type fills as referred to hereinafter) from a gelatin-containing material, typically in the form of capsules including hard and soft gelatin capsules, in a cost efficient and effective manner.
In a particular aspect of the present invention there is provided a method and apparatus for recovering non-solvent fills from a gelatin-containing material comprising:
a) adding the gelatin-containing material to a suitable solvent to form a mixture including a solvent phase and a phase containing said non-solvent fill;
b) separating the solvent phase from the phase containing said non-solvent fill; and
c) recovering the non-solvent fill.
The process more specifically comprises adding gelatin capsules, with or without prior xe2x80x9cgrindingxe2x80x9d thereof, to a suitable solvent (e.g. deionized water) typically in an amount of up to 5.0 volumes wt/wt, preferably from about 0.5 to 3 volumes wt/wt based on the quantity of capsules being processed. The addition step is typically carried out in a vessel at a temperature from about 40xc2x0 C. to 70xc2x0 C. with agitation, preferably by using a sweep mixer which is incorporated into the apparatus illustrated in FIGS. 2 and 3, at typically from about 5 rpm to 40 rpm to facilitate release of any residual non-aqueous fill from the aqueous phase and/or to homogenize the aqueous phase for enhanced processing. The above recited temperature and agitation are maintained until the capsules at least substantially dissolve which typically takes from about 15 to 60 minutes.
After dissolution, while maintaining the vessel temperature at from about 40xc2x0 C. to 70xc2x0 C. agitation is stopped and the dissolved capsules are allowed to at least substantially separate into a lower aqueous phase containing water, gelatin, plasticizer and, if applicable, dyes and other water soluble components and an upper phase containing the non-aqueous fill.
The separation may be achieved in any conventional manner including physical separation via a sight glass, using an apparatus such as that illustrated in FIG. 2, or through a mechanical skimmer such as an oil skimmer. The separation can also take place through various mechanical techniques such as, but not limited to, liquid-liquid centrifugation. Alternatively, the lower aqueous phase may be cooled and solidified and the non-aqueous phase collected by decanting or pouring from the top of the vessel using an apparatus such as that illustrated in FIG. 3.
The non-aqueous phase thus separated may be further processed to remove any residual water, especially if the fill is hygroscopic. This optional step may be conducted, for example, by treating the non-aqueous phase with molecular sieves or drying agents such as, but not limited to, magnesium sulfate. Other methods to remove the residual water from the non-aqueous phase include heating the non-aqueous material at or about atmospheric pressure, or under vacuum using an apparatus such as that illustrated in FIG. 4, preferably operating at a pressure of from 22 inches to about 29 inches of vacuum, at a temperature from about 40xc2x0 C. to 105xc2x0 C. for a period of time sufficient to remove the residual water, typically from about 30 minutes to 24 hours, to form an at least substantially dried non-aqueous phase.
The thus recovered non-aqueous fill may then be filtered, to remove any residual particulate matter which may be present, and reused in the capsule filling process. The aqueous phase may be optionally processed to recover the gelatin and plasticizer and, if applicable, dyes and other water soluble components so that these components may be recycled as well.